Over time, the chemical composition of drinking water passing through metallic pipes will lead to corrosion of and/or a scale formation on the interior walls of the conducting pipe system. In residential or industrial buildings, dissambling and rerouting of the water-conducting pipe system would entail extensive labor and expense while posing an extreme inconvenience to the tenants being serviced by this system.
The hardness of water being conducted through these pipes varies widely from very-soft to very-hard depending on the geographical region of where the source originates. Very-soft to soft water, i.e. water containing little or no magnesium or calcium, attacks the interior surface of the pipes resulting in metal-dissolution over the entire wetted surface. This debris is then carried through the pipes to the eventual user of the water.
With medium to hard water, there is often an interaction between corrosion and the formation of a protective layer. As a result, blister-like corrosion products form and attached to the wetted portions of the pipe. These products will lead to the subsurface formation of rust, they may be conveyed by the water flow and precipitate on bare metal surfaces, or they may ultimately be discharged to the consumer.
When conducting hard to very-hard water through the pipe system, a buildup of scale formation or deposits will occur. Additionally, this phenomenon will be enhanced with even a slight rise in temperature thereby accelerating the precipitation of carbonate, whereby, as a rule, oxidation cannot take place. These scale formations or deposits will grow continuously ultimately resulting in the clogging of the pipes or similar undesired consequences in a relatively short period of time.
As stated above, an increase in the temperature of the system will result in the acceleration of the chemical and electro-chemical reactions taking place. Consequently, the hot water system of a heating plant evinces, after only a short period of time, material destruction or scale formations while the cold-water wing remains relatively stable. Similar occurrences are evident in household systems wherein the hot water heater and hot water pipes become corroded while the cold water pipes remain clear.
European Patent Application No. 0 090 384 discloses a method of internally sealing pipes which conduct gas, and more specifically, residential gas lines where leakage in those lines has exceeded a predetermined value. This method however, is solely applicable to low pressure gas lines and not for use in pipes for conducting water or other liquid media which is often highly corrosive and conveyed at a high pressure.
Clearly, there is a need for a method of cleaning and coating the internal surface of water-conducting pipes, so as to reduce the contamination of the water and render extensive disassembling and rerouting of pipes unnecessary.